特集 超薄膜の構造と機能 有機高分子非線形光学材料：最近のトピックス

Abstract

The present review is mainly concerned with the macromolecular organic nonlinear optical materials for frequency doubling. Organic polymer materials are expected to apply the optical devices for the transparent, easy processability and so on. Recently some studies were carring out about the polymer, chromophore and device structures. These topics are introduced in this review. One of the major problems for poled polymer systems is the lack of thermal stability after aligningchromophore units. In order to prevent the decay, some ferroelectric or crosslinkable polymers carrying chromophore moiety were prepared. They showed large d coefficients and stability. Previously, the chromophores having shorter absorption wavelength band than the harmonic wavelength have been used. However, it has made possible to apply the longer absorption wavelength chromophores by using Cherenkov type phase matching. Besides, it has reported that the novel two-directional charge transfer molecules possessed large off-diagonal, β components has shown a small decay of d 33 even when the order parameter has relaxed. In optical waveguide structure, quasi phase matching accomplished by periodically poled or bleached waveguide structure was effective method to obtain harmonic light. As the practical and adroid method to achieve phase matching in waveguide, a attempt was made to adjust and suppress the phase matching condition by continuing to apply external dc voltage during frequency doubling. The guide-layer made of low Tg polymer was effective for quick response of chromophore alignment and change of refractive index against external electric field.